space-grid

v0.0.1

A very simple spatial grid implementation, designed to speed some calculations. Every cell is either empty or contains one item. This can speed up spatial calculations by focusing on just a few cells, instead of all of space.

API

This module exposes a single constructor, Grid. Every grid has a grid property, that is an object. All of space is divided into cells of customizable size, referenced by a string in the following format: x,y, where x and y are the indices of the cell.

Examples (with cell size 10x10):

• A point at (5, 5) would fall into cell 0,0
• A point at (20, 20) would fall into cell 2,2
• A point at (-11, 34) would fall into cell -2,3

Note: the methods add, remove, get, hasItem and isEmpty have corresponding methods that take in cell indices instead of point coordinates. These methods have the same name, but with an I (capital i) appended, so add becomes addI.

Note: unless otherwise noted, methods return this, for chaining.

new Grid(number cellWidth, number? cellHeight)

Makes a new Grid.

• cellWidth: the width of the cells
• cellHeight the height of the cells. If not provided, falls back to cellWidth

grid.reset()

Reset (empty) the grid.

grid.size(number cellWidth, number? cellHeight)

Sets the size of the grid and calls grid.reset().

• cellWidth: the width of the cells
• cellHeight the height of the cells. If not provided, falls back to cellWidth

grid.str(number x, number y) : string

Returns the unique name of the cell a point at (x, y) would fall into, in the following format: x,y (as a string).

grid.add(any item, numer x, number y)

Adds item to the correct cell (i.e. the cell a point at (x, y) falls into).

grid.remove(number x, number y)

Remove the item from the cell a point at (x, y) would fall into, if any.

grid.get(number x, number y) : any

Get the item from the cell a point at (x, y) would fall into.

grid.hasItem(number x, number y) : boolean

Check whether the cell a point at (x, y) would fall into contains an item.

grid.isEmpty(numer x, number y) : boolean

Check whether the cell a point at (x, y) would fall into is empty (i.e. the opposite of hasItem).